This paper proposes an inter-vehicle communication (IVC) scheme for safety driving support systems that transmits collision avoidance warnings at intersections. In order to realize high communication reliability, a transmission scheme based on multiple-input multiple-output (MIMO) with space-time block coding (STBC) is proposed. A key transmission feature of MIMO systems is determined by radio wave propagation. Therefore, the radio wave propagation at an intersection is analyzed by computer simulations using the ray-tracing method. In addition, this paper verifies the effectiveness of the proposed scheme using the propagation characteristics in computer simulations

Mobile reception of digital terrestrial broadcasting carrying an 18-Mb/s digital HDTV signals is achieved. The effect of diversity reception in moving automobiles for a 64 quadrature amplitude modulation-orthogonal frequency division multiplexing (QAM-OFDM) signal is investigated by prototype hardware. There are two methods for diversity reception of OFDM signals. The first is the Doppler compensation directivity control system. For this method, high-performance on-glass antennas and new diversity reception systems for OFDM reception have been developed to verify HDTV service availability in mobile reception environments. Novel horizontally polarized on-glass antennas suitable for DTV were developed. The antenna elements were printed on the inside surface of the rear window glass of a passenger van. OFDM signals received by the four antenna elements were weighted and combined using maximal ratio combining (MRC). The experiments were conducted in urban areas and they showed that employing diversity techniques would make HDTV mobile reception possible in many areas. The other method is post-FFT diversity. In the receiver, MRC is performed after an FFT operation on each branch signal. Experimental results show that accurate HDTV mobile reception can be achieved by using a four-branch MRC system. Also, the minimum usable electric field strength could be reduced compared with that of a single dipole antenna.